Bits of .NET

Including build tools in final image wastes space. Multi-stage builds separate build and runtime.

Single-Stage (Large):

FROM node:18
WORKDIR /app
COPY . .
RUN npm install  # Includes dev dependencies
RUN npm run build
CMD ["node", "dist/server.js"]
# Result: 1.2 GB (includes npm, build tools)

Multi-Stage (Small):

# Stage 1: Build
FROM node:18 AS builder
WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .
RUN npm run build

# Stage 2: Production
FROM node:18-slim
WORKDIR /app
COPY --from=builder /app/dist ./dist
COPY --from=builder /app/node_modules ./node_modules
CMD ["node", "dist/server.js"]
# Result: 180 MB (only runtime files)

85% smaller image!